Deep in the Chilterns in Bix Valley, Warburg is the place to enjoy butterflies on a sunny day. From down amongst the grasses along the woodland rides to high in the tree canopy, you can glimpse these beauties busily fluttering about.

At the reserve we try to provide all the things that butterflies need to thrive. Flowery grasslands which get lots of sun are a key part of the mix, along with brambles and some scrub to provide shelter from the wind. Butterflies have specific plants on which their caterpillars feed so we encourage and cater for as wide a range as possible.

Fritillaries Along a woodland path only last week I saw a fritillary fly past. As it settled on a flower to suck up nectar I managed to get within a few inches on my hands and knees. It was a dark-green fritillary, and a pristine example at that. This mainly orange insect gets its name from the green tint and silver spots on its underside. Sadly numbers are in decline. The one you are more likely to see here is the silver-washed fritillary; equally stunning and fortunately doing rather better.

Pick of the purples The holy grail for many butterfly watchers is the male purple emperor, with its deep-purple iridescent wings. This magnificent insect spends a lot of time up in the tree canopy, gliding between trees and feeding on the sugary honeydew secreted by aphids. They do come down to ground level to bask, but you need a bit of luck on your side to see one.

The purple hairstreak spends even more of its time in the canopy, usually on oak trees. These are small butterflies so you need binoculars and it can be a frustrating business getting a good view! Most of my sightings of rarities happen by chance; children I was walking with spotted one sitting on a leaf just at eye level and I was able to get a close look.

A white-letter day Last year was a good year for white-letter hairstreak, another rarity which spends most of its time up at the top of elm trees. One day I was fortunate enough to see three and close enough to ‘read’ the white letter ‘W’ on the wing which gives the butterfly its name. No sightings of it this year — but there’s still time! Most of these species are pretty rare. To increase your chances of spotting them, choose a warm day without too much wind and do take your binoculars. If you don’t happen to see any rarities don’t be disappointed; many of our more common species are equally beautiful.

What could be better than the electric brilliance of a fresh common blue or the jewel in the grass that is the small copper? If you would like to visit a wildlife trust nature, become a member or join a guided walk, please visit www.bbowt.org.uk or tel 01865 775476.